Matic electric inc



18 1927. Oct J. WICKS AU'ItOMATIf) TELEPHONE SYSTEM M PB L645, Oct. 18, 192?. J. W'CKS v 636 AUTOMATIC TELEPHONE SYSTEM Ori inal Filed y 8. 1921 s Sheets-Sheet 2 I'm-*- Jnhn hicks lmsma I 18 19 Oct 2 J. WICKS AUTOMATIC TELEPHONE SYSTEM 3 Sheets-Sheet 5 Original Filed July 8. 1921 uumu -mmnm Patented Got. 18, 1927.

htttifififi PATENT OFFEQE.

JOHN WICKS, OF .OAK PARK, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO AUTO-- MATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

AUTOMATIC .TELEIHONE SYSTEM.

Application filed July 8, 1921, Serial No. $8,361. Renewed January 25, 1926.

I also are established automatically. The object of the invention may be said to consist in the production of new and improved cir cuit arrangements whereby the usual cord circuits at the toll operators position, as well as their corresponding jacks, are entirely eliminated.

The above indicates in general terms the scope of the invention. Various features ineluded in the working of the complete system will not now be specifically mentioned but will be described in the specification which is to follow, and pointedout in the claims.

Of the accompanying drawings to which reference will be made in the specification, Figs. 1 and 2, when arranged in order with corresponding lines at the ends thereof in alignment, represent diagrammatically a toll line extending between two more or less widely separated exchanges in a system em bodying the principles of the present invention, together with suflicient of the apparatus in each exchange to enable the invention to be understood. Fig. 3 is a schematic diagram illustrating the general layout of the system.

Referring to Fig. 3, three automatic exchanges are shown which, beginning at the left, will be designated respectively, as the No. 1 exchange, the No. 2 exchange, and the No, 3 exchange. These exchanges are assunicd to be located in different cities and, although the exact size is of no great consequence, they are assumed to have a capacity of 10,000 lines each. With the capacity as above noted, local connections are established through the medium of individual line switches or trunk selectors, first selectors, second selectors, and connectors. For example, the subscriber at substation A, in the No. 1 exchange, is able to establish connection with the subscriber at substation A through the medium of the individual line switch C, first selector E. second selector F,

and the connector H. This is the usual percentage trunking system and is mentioned because of the fact that the greater portion thereof comprising the second selectors'and connector switches is used also in establishing incoming toll connections.

Each exchange is provided with a toll board presided over by one or more operators who establish all outgoing toll connections. The operators in the No. 1 and the No 3 exchanges have access to the local subscribers lines by way of an incoming toll first selector, such as the selector E or the selector E and thence by way of the regular trunking system. In exchange No. 2, however, the toll operators obtain connection with the subscribers lines through a separate trunking system which is commonly known as a toll service trunking system. In such a system the circuits of the switches are changed slightly as will be pointed out hereinafter; the connector H, for example, a combination toll and regular connector, acts somewhat differently when used by a toll operator than it does when used by a subscriber. Accordingly an operator in exchange No. 2 extends a connection to a sub-- scriber, the subscriber at substation A for example, by way of either toll first selector or toll first selector E, toll second selector F and the combination toll and regular connector H. It is to be-understood of course that the installation of a separate toll service trunking system in any of the three exchanges shown is a matter of choice; however, in the exchanges that have sufiicicnt outgoing toll traflic to warrant. the

added expense, a toll service trunking svs tem is to be highly recommended because such a trunking system is better suited to the operating requirements and also because of the fact that better transmission is afforded when a toll service trunking system is used than is possible when only the regular trunking system is used.

Proceeding now to the trunking between exchanges, the No. 1 and the No. 2 exchange are interconnected by a group of toll lines suflicient in number to handle the traffic. One of these toll lines is the toll line Similarly another group of toll, lines, of which the toll line Z is one, connects the No. 2 exchange and'the No. 3 exchange.

There are no toll lines directly connecting the No. 1 and the No. 3 exchanges and therefore connections between these two points must necessarily be extended by way of the No 2 exchange.

The toll lines, which heretofore have terminated at each end in the usual manual jacks, terminate in operators controlling (Bil Hit]

key circuits instead. The trunk line X, for example, extends from the operators controlling key circuit 0 in the exchange No. 1 to the operators controlling key circuit 0 in the exchange No.2. Similarlythetrnnkline Z extends from the operators controlling key circuit 0 in the No. 2 exchange to the operators controlling key circuit in the No. 3 exchange. In addition to terminating in the before mentioned operators controlling key circuits, the toll lines X and Z terminate at each end in an automatic repeater such as the repeaters D, D, D and D as is clearly shown in the drawings. Each of these repeaters is associated with a first selector such as the selectors E, E, E, and E The first nine levels of the banks of these switches are connected in multiple with the first nine levels of the banks of the regular first selectors, as the drawings clearly indicate. Since the toll operators are never required to call the toll recording operator, who is reached by the subscribers by dialling 0, there is thus left available for other purposes the tenth level of the toll first selectors. In the No. 2 or intermediate exchange this level is used for through sivitching and for this purpose a group of toll switching selectors is provided, one of which is indicated by the reference character F These toll switching selectors are accessible in common-to all the incoming toll first selectors in the No. 2 exchange and have common access to all the groups of toll lines terminating in the No. 2 exchange, it being understood of course that there may be a number of such grouis, each extending to a different city, in addition to the two groups indicated in Fig. 3 No toll switching selectors are shown in either the No. l or the No. 3 ciuil'iange. in case the e should be a fourth exclnuigc, the lilo. 25 ex,- change would take on the character ot an intermediate cxchai'ige and would be equipped with. toll switching selectors in the same manner as the excl'iange No. it, and if there should be another exchange similarly located, with respect to the No. 1 exchange, the No. 1 exchange also would take on the character of an intermediate ex change. It is now seen that the incoming toll first selectors in the No. 2 exchange are used not only for completii'ig toll coin trons to subscribers in that exchange, but

' connection, it may be said, is completed by the operator in the No. 2 exchange and is extended to the called substation over the following path: the left hand end of the operators controlling key circuit O, automatic repeater D, trunk line X, automatic repeater D, incoming toll first selector E, second selector F and connector H. The connection to the local subscriber in the ex change No. 2 is set up over the toll service trunking system and when completed may extend over the following path: right hand end of the operators controlling key circuit 0', toll first selector E toll second selector F, and combination toll and regular connector I-I'. Assuming now that the called subscriber is in the exchange No. 3 instead of the exchan e No. 1 the connection to the called subscriber may be set up over the following path: the right hand end of the operators circuit 0 repeater D trunk line Z, repeater D incoming toll first selector E second selector F and connector H In this case the connection to the local subscriber in the exchange No. 2 may be tended over the following path: the left hand end of the operator's circuit tell first selector E, toll second selector F, and combination toll and regular connector ll. Assuming, now that the toll operator in exchange No. 1 extends a connection from a substation, the substation A for example, in exchange No. 1 to a substation in exchange No. 2, the substation A" for exal'l'iple, she sets up the connection to the called substation over the following path the right lzanzl' end of the operators controllii I key circuit 0, repeater D, trunk line X, repeater l), incoming toll first selector E, second. selector F and connector H. The connection to the local subscriber at substation A is set up over the following path: the left hand end of the operators controlling key circuit O, incoming toll first selector E, second selector F, and connector H.

Assuming now that the called substation is a substation in exchange No. 23', the sub station A for example, the connection may be extended over the following path: the right hand end of the operators circuit 0, repeater D, trunk line X, repeater D, incoming toll lirst selector l l. toll switching selector F repeater D toll line Z, repeater D, incoming toll first selector 1G5, second selector F", and connector H i'issun'iing that the toll operator in exchange No. 3 estahlisl ,r a crnincction between a substation in the tame QXCllfli" the substation A for example, and a substation in exchange No. :2. the substation A for ertainple, she may set up the connection to the latter or called substation over the following path: the left hand end of the operators controlling key circuit 0, repeatcr D the trunk line Z, repeater D incoming toll first selector I regular secnd selector F, andconnector H. The connection to the local subscribe is; extended over the following path: right hand end of the operal'orscircuit O incoming iirst elector lu second selector F and connector H in case the called subscriber is a subscriber in exchangello, 1, the subscriber at substation A, for-example, the connection to the called substation is set up over the following path: left hand end of the operators controlling hey circuit 0*, repeater D toll line Z, repeater D inconr .ingtoll first selector E", toll switching se- 1), l1100111il'1g' toll first selector E, second sethat the foregoing is sutficient to malre clear the general layout of the system.

) rence will now be had to the circuit n91 drawings comprising Figs. 1 and 2, for a description of the new apparatus involv d. l hese drawings show diagrammatically all the new circuits associated with a toll line in a system embcd ing the principles of the invention, which is the system shown scheinaticallyin Fi 3. V

The apparati shown in Fig. 1 is located in the No. 1 exchange, and the apparatus shown in Fig. 2 located in the No. 2 exchange. It will be noted that the corresponding parts. are cross referenced between Figs. 1 and 2- and Fig.3 so that they are easi located on either. Referring now particularly to Fig. 1 the operators controlling hey circuitO shown therein is very much similar to, and in fact may be practically a duplicate of the cord circuit which would otherwise be used for the same purpose.

lhis controlling hey, circuit, however, as has been mentioned hereinbefore, unlike acord circuit has each end permanently associated with a particular trunk line, and consequently individual thereto instead of being common to a numl'ier of trunk lines. As shown, the right hand end of'the con trolling key circuit 0 is permanently associated with the right hand end of the repeater and consequentlywith the toll line while the left, hand end of the key circuit O is associated with the trunk line comprising conductors 93-95 inclusive. The said trunk line is understood to extend to and terminate in an incoming toll first sclector such as the selector E, Fig. 3. This selector switclntogether with the selectors E, E E E E E F, F, F and F of the well known vertical and rotary type and the circuit. thereof may be the same as that, of the selector E disclosed in the United States patent to lVillis No. 1,2T7,675, granted Sept. 8, 1918. The circuit of each of the connectors H and H to which the selectors F and'F, respectively, have access may be'the sameas'the circuit of the conlector F repeater D, toll line X, repeater ncctor H shown in the patent referred to.

The circuits of the operators equipment 0 are shown complete and will be fully described later.

The repeater D in which one end of the toll line X terminates in a two way automatic repeater and is used to translate loop diallingimpulses into simplex dialling impulses and vice versa, and for several other purposes which will be more fully pointed out later. She repeater D, Fig. 2, on the other end of the toll line X and in exchange No. 2 is an exact duplicate ofthe repeater D but the operators circuit 0 differs from the operators circuit O in that the right hand or local end thereof, instead of bein used for operating switches in the rcgula trunking system as the local end of the op crators circuit O is designed to do, is used for controlling switches in the previmwfy mentioned toll service trunking system. Reference will now be had to my prior United States patent, No. 1,315,444, grantee Sept. 9, 1919, in which Figs.1, 2 and 3 show a complete connection from a toll operators position to a called substation by way of a toll service trunking system. The operators circuit 0, shown in the presentdrawings, is designed to cooperate with such a toll service trunking system, and accordingly the selectors and E shown in Fig. 3, of my present applieationare assumed to have circuits substantially like that of the selector V, Fig. 2, of the patent last referred to.

HUG

7 Similarly the toll second selector F and the combination toll and regular connector H shown in the present drawings are assumed to have circuits COII'QSPODCllIlg respectively to those of the toll second selector lV and the combination toll and regular connector H which also are shown in the patent last referred to.

In the lower left hand corner of Fig. 2, three bank contacts 190-192, inclusive, are shown. These bank contacts, it may be said, are assumed to be in the bank of a toll switching selector such as the selector F Fig. It, is to be understood that the repeater D in exchange No. 1 would be similarly equipped with normal conductors, which would extend to and terminate in bank contacts of toll switching selectors, if the exchange No. l were an intermediate exchange.

The apparatus having been vdescribed in a somewhat general manner will now be described more specifically in connection with a detailed description of its operation. F or this purpose it will be assumed that the subscriber at substation A, Fig. 3. in exchange No. 2 desires to converse with the subscriber at substation A in exchange No. 1. Upon removing his receiver, the subscriber at substation A? is automatically connected with a first selector such as the selector E by his individual line switch or trunk selector G The subscriber at substation A now dials the digit whereupon the selector E assuming that this switch has been selected, raises its wipers to the tenth level and rotates them in search of an idle trunk line extending to the toll recording ope 'ator. This part of the operation is old, and the apparatus used therein forms no part of the invention, but is pointed out merely because of the fact that it is so closely related with what is to follow. To continue, when the toll recording operator answers she converses with the subscriber at substation A and after finding out his number and the number of the subscriber with whom he desires to converse and the exchange in which the latters line terminates, she may, and we shall assume that she does, make out a ticket containing the necessary information. The recording operator now passes the previously mentioned ticket over to a toll operator in exchange No. 2* and tells the calling sub scriber to replace his receiver and wait until he is called by the toll operator. hen the subscriber at substation A replaces his receiver upon the switchhook the established connection is released.

The toll operator in exchange No. 2, upon the receipt of the before mentioned ticket, throws her key K into the call. out position thereby operating the springs 161-163, inclusive. Spring 163, upon operating, closes a circuit for release relay 17 2 in series with the resting contact of spring 160 of the release key K and said spring. Upon energizing. release relay 172, at arn'iatures 177 and 178 places the following bridge across the conductors 193 and 195: from conductor 195 by way of the working contact of armature 178 and said armature, the working contact of spring 162 of key K and said spring, the secondary or right hand winding of the induction coil associated with the ope-rators head set, resting contact of spring 106 of key K and said spring, impulse springs of the calling device S, spring 167 of key K and its resting contact, spring 161 of key K and its working contact, and armature 177 and its. working contact to corn ductor 193. As a turther result of the encrgization oi? relay 172 it places ground on re lease trunk conductor 194 of the repeater D, at armature 179. This ground potential extends to the test contact 191 and its multiples in the banks of the toll switching selectors thereby causing the trunk line X to test busy to the said toll switching selectors in the usual manner. As a further result of the placing of a ground potential on the release trunk conductor 194 a circuit is closed for the left hand or polarizing winding of the electropolarized supervisory relay 17 4 of the operators circuit 0, and also for the upper or polarizin winding of electropolarized relay 111 of the repeater D. The polarizing winding, however, consisting ofa small nu1nber of turns of high resistance is not able to energize the relay in either case. As a still further vresult of the placing of the ground potential on release trunk conductor 194, relay 102 of repeater D is energized over the following circuit: from ground, by way of release trunk conductor 194, armature 129 of relay 108 and its resting contact, and relay 102 to battery. Relay 102, upon energizing, opens the normally closed bridge across ctmductors 193 and 195, at armatures 113 and 114, and places the upper and lower windings of line relay 104 in bridge of the said conductors instead, the bridge in either case including the right hand windings of repeating coil T. Line relay 104 immediatelyenergizes over the previously traced bridge across the conductors 193 and 195 in the operators circuit 0 and closes a circuit for the release relay 105, at armature 120. Upon energizing, relay 105 prepares a circuit for relay 106, at armature 122; and closes, at armature 123, a. circuit which extends trom ground by way of the said armature and its working contact, and the resting contact of armature 108 and said armature, to release trunk conductor 194. By means of this ground on the release trunk conductor, release relay 172 of the operators circuit 0' is maintained energized and the trunk line is kept busy, after the key K is restored to normal position, which occurs subsequently. As a further result of the energization of line relay 104 it completes, at armature 119, the following circuit for the supervisory relay 109 of repeater D and line relay 24, of the repeater D. From ground by way of the upper winding of line relay 24 of repeater D, resting contact of arn'iature 32 and said armature, resting contact of armature and said armature, resting contact of armatue 52 and said armature, upper and lower right hand windings of the repeating coil T, upper and lower conductors of the trunk line X, upper and lower left hand windings of the repeating coil T, ari'nature 1.12 and its working contact, armature 11.9 and its working contact, and the lower winding of supervisory re'lay 109 to battery. Line relay 24 of repeater D and supervisory relay 109 of repeater D energize in series over the above traced circuit. Supervisory relay 109, upon energizing, closes, at armature 133, a circuit extending from ground by Way of release trunk conducto-r 194, working contact of armature 133 and said armature, and relay 110 to battery. Relay 110 uponenergizing' closes a locking" circuit for itself at armature 137 and closes a point in the circuit of reversing relay 103, at armature 135. The said reversing relay ltltl eludes the lower winding of electropolarized relay 20, resistance 57, and the left hand windings of the repeating coil T. This is the usual expedient made use of in order to obtain tirst classswitch control. 'As a result of the interruptions produced in the circuit of the line relay of selector E, the said switch raises its shaft and wipers step by step until they come to rest opposite the desired level of bank contacts and, upon the cessation of the series of interruptions, rotates the said wipers in search of an idle trunk line.

lVe shall assume in the present case that the digit that has been called is 1 and that the second sele'ctor'F the first one found to be idle and consequently is the one selected. The line and release relays of selector F now energize thus preparing the switch foroperation and establishing a hold: ing circuit of the selector E in the usual manner. I

The toll operator in exchange No. 2 may now operate her calling device in accordance with the second digit of the desired number, whereupon selector F, in exchange No. 1, is caused to raise its shaft and wipers i-tep by step until the latter stand opposite the de sired level of bank contacts. In this case also, we shall assume that the digit called is gize and prepare the switch for operation,

at the same time closing a holding circuit for the switches E and F in the usual man ner.

The operator may now manipulate her calling device in accordance with the third digit of the desired number, vhereupon the connector H raises its shaft and wipers step by step until the latter stand opposite the desired level of bank contacts, being in this case the level in which the line of substation A terminate The operator may now turn the dial of her calling device tor the next and final digit of the desired number, whereupon the wipers of the connector H are rotated step by step until they finally come to rest upon the desired set of contacts, or the one in which the line of substation A terminates. Assuming that the line of substatior A is idle, the connector H sends ringing current out intermittently to ring the bridged bell at the called substation,

The operator, having finished calling the number, returns her key K to normal position thereby shitting the bridge across conductors 193 and 195 so as to include the normally closed contacts controlled by spring 162, the right hand winding of electropolarize ii'elay 174, impedance 1.73, and the normally closed contacts controlled by spring 161. The electropolarized relay 174 now energizes because the current flowing in its right hand winding is in such a direction as to assist the current flowing in its left hand winding. Upon energizing, relay 174 closes, at armature 180, a circuit for supervisory lamp L and the said lamp accordingly becomes lighted.

Vhen the subscriber at substation A removes his receiver, in response to the ringing of his bell, the back bridge relay of the connector H energizes in the usual manner and reverses the incoming line conductors as regard-i their connection with the windings of the line relay ot' the said connector. In the repeater D electropolarized relay 20 now energizes in response to this reversal since its two windings, which here totore haveopposed each other, are now energized in such a Way as to assist each other. Upon energizing, relay 20 closes a locking circuit for line relay 24, at armature 19; and, at armature 30, removes the upper winding of line relay 24 tron'i the control circuit and substitutes the upper winding of supervisory relay 22 therefor. It will be noted that, since the upper winding of supervisory relay 22 is connected to the same pole of battery as the lower winding of supervisory relay 109, no current flow: over the toll line X and consequently relay 22 does not energize and supervisory relay 109 deenergizes. Supervisory relay 109, upon deenergizing, completes the circuit of reversing relay 103, at armature 132, as follows: from ground by way of armature 123 and its working contact, armature 124: and its resting contact, resting contact of armature 132 and said armature, working contact of armature 135 and said armature, and reversing relay 103 to battery. Upon energizing, rever ing relay 103 reverses, at arniatures 117 and 118, the conductors lead ing to the upper and lower windings of line relay 10* as regards their connection with the said windings, thereby causing a reversal oi current in conductors 193 and 195 and likewise in the bridge across these conductors in the operatmrs ircuit O. Electropolarized relay 174 new retract; its ar'matiiire 130,

since the current flowing in each of its windings opposes the current flowing in the other, thereby extinguishing the supervisory lamp L The operator, upon noting that the supervisory lamp L has become extinguished, knows that the called subscriber has answered and, accordingly, she throws the key K to listening position thereby placing her head set in bridge of the heavy talking conductors 193 and 195, at springs 164 and 165. The called subscriber and the toll operator may now converse with each other, the talking circuits, that are shown, being outlined by the heavy conductors. The toll operator tells the called subscriber to wait on the line l ll) while she extends the connection to the subscriber who desires to converse with 111111.

The operator may leave her listening ltey thrown, if-she so desires. In any event she is the one selected.

throws the key K into calling posit-ion thereby operating the springs 166168, inclusive. Spring 168, upon being operated, closes a circuit for release relay 176, in series with spring 171 of release .key K and its resting contact. lease relay 176 prepares a locking circuit for itself, at armature 182; and, at armature 183, places ground 011 the operating conductor 198, by way of the following circuit: from ground, by way of the working contact of spring 167 and said spring, impulse springs of calling device S, spring 166 and its working contact, and armature 183 and its working contact, to conductor In the toll first selector E Fig. 3, the line and release relays immediately energize and prepare the switch for operation in the usual manner, and the latter places ground on the release trunk conductor 197 thereby closing a locklng circuit for release relay 176 independent of spring 168 of key K The operator may now turn the dial of the calling device S in accordance with the first digit of the desired number thereby interrupting the circuit of the. line relay 0t selector E a corresponding number or times. In response to these interruptions, the said line relay causes the said selector E to raise its shaft andwipers step by step until the latter stand opposite the desired level of bank contacts. Atthe end of the series of impulses the wipers of the said selector are rotated automatically; to pick out an idle trunk line terminating in the level of con tacts opposite which they; are raised. In the present 'case'we shall assume that the wipers of switch E are raised opposite the level in which the trunk line extending to tell second selector l5 terminates and that the said selector F is the first one found idle and consequently the one selected.

The operator may now call the next digit,

"whereupon the selector F responds by raise ing its shaftand wipers until the latter stand opposite the desired level of contacts, which in this case we shall assume is the level in which the trunk line extending to the connector H terminates. WVe shall assumefurther that, when the wipers of the said selector are rotated at the end of the series of impulses to pick out an idle trunk line, the trunk lineleading to the connector II is'the first on found idle and therefore The. connector, H now preparesitselr' for operation in theusual manner.

In response to the last two digits of the called number, the connector H is assumed to raise its wipers to the desired level and Upon energizing, re

rot-ate them until they finally come to rest on the set of contacts inwhichthe line of substation A terminates.

The operator, having called the desired number, throws her key K to the opposite or ringing position, thereby sending ringing current out over the established connection to the connector H. Before describing the efi ect produced in the said connector, we shall consider the circuit changes caused by springs 166468, inclusive, returning to normal position. It will be noted that, with thespring 166 in normal position the operating conductor 198 is grounded by way oi the marginal supervisory relay 175. It may be stated that the operating conductor at this time extends to battery at the other end through a relay of comparatively low resistance, and accordingly supervisory relay 175 is energized immediately upon the restoration of spring 166 to normal position thereby closing the circuit of supervisory lamp L. Supervisory lamp If now lighted.

When the ringing current is projected out over the established connection, as hereinbeforc described, a ringing responsive relay is caused to energize with the final result that ringing current is sent out to ring the bridged bell at the called substation. lVhen the ringing key is restored to normal position, the ringing responsive relay deenergizes with the final result that ringing current is removed from the called line. The op eration may be repeated as many times as may be necessary.

When the called subscriber answers, the battery feed relay, which is in the toll second or transmission selector, energizes with the. final result that the heavy talking conductors 196 and 199 are connected up so that they extend from the right hand end of the. operators circuit 0 to the substationA As a further result of the energization of the battery feed relay, sutficient resistance is inserted in the operating conductor 198 to cause the marginal supervisory relay 175 to deenergize and extinguish the lamp L thereby giving the operator answering supervision.

The complete connection is now established between the substation A in exchange No. 2 and substation A in exchange No. 1 and the subscribers thereatmay converse as desired, the talking circuits, that are shown, being outlined by the heavy conductors.

l hen the conversation is completed the two subscribers replace their receivers. lVhen the receiver is replac d at substation A", the betorementioned resistance, which was placed in the o3-erating conductor 198 responsive to the answering of the subscriber at substation A3, is removed and the normal resistance is reintroduced th who npon the marginal supervisory relay 175 energizes again and lights the supervisory lamp L. l

When the receiver is replaced at substation A the back bridge relay of connector H deenergizes thereby reversing the current How in the conductors 93 and 95 of the re peater D back to normal. Electropolarized relay 20 responds to the reversal of current by retracting its ari'i'iatures. At arn'iature 19, relay 20 opens the locking circuit of line relay 24; and, at arn'iature the said relay shifts the switch control circuit from battery, through the upper winding of relay 22, to ground by way of the upper winding of line relay 2 1:. Line r *lay 2a is new main tained energized in series with supervirisory relay 109 of repeater D. Supervisory relay 109, upon energizing, opens the circuit of reversing relay 103 at armature 132. Upon d-eenergizing, reversing relay 103 roverses the current tlow in the conductors 193 and 195 back to normal, whereupon electropolarized. relay 171 attracts its arn'iature and lights the su 'iervisory lamp L.

The toll operator, upon perceiving the lighted condition of lamps L' and L, knows that the conversation is finished and that the subscribers have replaced their receivers. In order to release the connection to the subscriber at substation A, the operator momentarily operates the release key K whereupon release relay 1? 6 deenergizes and, at ari'nature 182, opens its previously described locking circuit. As a further result 01" the deenergization of relay 176, it opens the operating circuit at armature 183, whereupon supervisory relay 175 deenergizes and extinguishes the supervisory lamp L". As a further result of the opening of the operating circuit, the established connection to the subscriber at substation A? is released and all the switches used therein are restored to normal position, in the usual man ner.

In order to release the connection extend ing to the substation A, the operator mo 1ncntarilv operates the key K whereupon release relay 17 2 deenergizes; opens its lock-- ing circuit, at armature 179; and, at ar1na tures 177 and 178, opens the bridge across line conductors 193 and 195 ot the repeater D, in response to which electropolarized relay 17 1- :talls back and extinguishes the su pervisory lamp L and line relay 104 of repeater D deenergizes. Upon deenergizing, line relay 10a opens the control circuit, at armature 119, whereupon line relay 24 oil repeater D and supervisory relay 109 of repeater D deei'iergize. As a further result of the deencrgization of line relay 104, it opens the circuit of release relay 105 and closes the circuit of slow acting relay 106, at armature 120. elease relay 105, upon deenergizing, opens the circuit of relay 100, at armature 122; and, at arn'iature 123, re-

moves ground from the. release trunk rouductor 191. The busy lamp L now becomes extinguished and the repeater D and consequently the trunk line X is caused to test idle to the selectors having access to it in exchange No. 2.

In the meantime the repeater D and its associated selector E, together with the switches F and H, in exchange No. 1, have restored themselves to normal condition as will now be explained. Line .relay 24, upon deenergizing responsive to the opening of the control circuit, as previously pointed out. opens the circuit o't release relay 23 and closes the circuit'of slow acting relay 25, at armature 11; and, at arniature 2%, opens the bridge across conductors 93 and 95 whereupon the switches E, F and H restore themselves to normal position in the usual.

manner. Release relay upon deenergiz ing, opens the circuit of relay 25, at armature 3S, and removes ground from conductor 91, at arn'iature 3?, thereby extinguinl'iing the busy lamp L All the apparatus used in extending the previously described connection new restored to normal condition.

Assun'iing now that the subscriber at substation A tails to replace his receiver atthe end ot the conversation, the parts of the releasing operation that ditl'er from these already explained will be pointed out. Since the current flow in the trunk line X. ceases entirely upon the answering of the subscriber at substation A, it easily seen that under these conditions, the mere opening of the control circuit does not affect the repeater D on the distant end of the toll line. Consequently if other means were not provided for releasing the connection, the toll line X would remain tied up.

Assuming that the operator initiates the release of the counrction, with the receiver still oitl at substation A, the repeater D" opens the control eirciijt and assumes normal cordition without having e'llected any change in the repeater D. Inin'iediatclyafter repeater D assumes uorinal condititui, however, line relay 107 energizes in series with siuiervisory relay 22 ct repeater D over the 'l' llo\\'ing circuit: from ground by way of the upper winding of line relay 107, resting contact of ari'i'iature 1'36 and said rinature, resting contact Off armature 138 and said arniiature, resting contact'of arir iture 112 and said armature, and thence by way 01 a previously traced circuit to battery, through the upper winding of supervi ory relay Line relay 1.07, upon energizing, closes a circuit for release relay 108, at arnurture 128. lay 108 places ground on release trunk conductor 194, at arntiature 129, thereby causing Upon energizing, release rethe re ieater D and consecuentl the toll line X, to t st busy to the having access to it, ant

lamp L again. As a further result of the completed across line conductors 100 and 101 thereby making the selector E (Fig. 3) ready for operation in the usual manner.

In the repeater D, supervisory relay 22, upon energizing, closes the circuit of relay 21, at armature 35, and opens the locking circuit of line relay 24, at armature 36. Relay 21, upon energizing, opens a point in the circuit of the upper winding of line relay 24, at armature 32, and locks itself to grounded conductor 91, at armature 33. Line relay 24, upon deenergizing, opens the bridge across conductors 93 and 95', at arma ture 40, and opens the circuit of release relay 23, at armature 41. In response to the opening ofthe bridge across conductors 93 and 95, at armature 40, electropolarized relay 20, which is adjusted so as not to hold up with only its polarizing winding ener gized, falls back and, at armature 19, opens a point in the circuit of the lower winding of line relay 24 and, at armature 30, opens the control circuit, whereupon supervisory relay 22ot repeater D and line relay 107 of repeater D deenergize. Supervisory relay 22, upon deenergizing, opens the initial circuit of relay 21, at armature 35, but the said relay 21 is maintained energized by means of its previously mentioned locking circuit. With relay 21 energized it will be noted that the circuit of the upper Winding of line relay 24 is held open, at armature 32, and consequently any capacity discharge through the upper winding of line relay 24 from the toll line X, due to the control circuit being shifted suddenly from battery to ground by armature 30 of relay 20, is avoided. Release relay 23 now deenergizes in response to the opening of its circuit, at armature 41 of line relay 24, andr-enioves the ground potential from conductor 91, at armature 37, whereupon relay 21 deenergizes and, at armature 32, extends the control circuit to ground by Way of the upper winding of line relay 24. The time required by the slow acting release relay 23 to fall back gives ample time for any dis charge that might result from switching the control circuit from battery to ground, to pass to ground through the upper winding of line relay 107 of the repeaterD.

It has been found that it the above mentioned precaution is not taken, line relay 24 is kicked up again, followed by the energization of relay 20 which switches the control circuit back to battery again, and the operation is repeated over and over.

In regard to the switches E, F and H, it may be stated that they all release in response to the opening of the bridge across conductors 93 and 95 at armature 40 of line relay 24.

In the rep ater 1)., as a result of. the deenergization of line relay 107, the said repeater and its associated selector assume normal condition.

e shall now assume that the subscriber at substation A 111 exchange No. 1 desires to ,call the subscriber at substation A in exchange No. 2. In order to do this, he calls the toll recording operator in the usual manner and the toll recording operator makes out a ticket or in some other way passes the information she obtains over to the toll operator in exchange N0. 1.

In order to call the subscriber at substa tion A in exchange No. 2, the toll operator in exchange No. 1, assuming that the toll line X is idle as indicated by the unlighted condition of the lamp L may throw the key K to the call out position, thereby operating the springs 7375, inclusive. Spring 75, upon being operated, closes a circuit for release relay in series with spring 76, of release key K and its resting contact.

Upon energizing, release relay 80 places ground on conductor 91, at armature 88, thereby preparing a locking circuit for itself and closing an energizing circuit for busy lamp L This ground potential extends to the polarizing winding of the elec tropolarized relays 79 and 20 but these relays are not energized by their polarizing windings alone because of hereinbefore given reasons. As a further result of the energization of release relay 80, it places the following bridge across conductors and 92: from conductor 92, by way of the working contact of armature 87 and said armature. working contact of spring 74 and said spring, impulse springs of the calling device S, the resistance associated with the left hand or secondary winding of the operators induction coil, the said winding, spring 73 and its working contact, and armature 88 and its working contact, to conductor 90.

In the repeater D, as a result of the placing of ground upon conductor 91, a circuit is closed from ground by way of conductor 91, armature 37 and its resting contact, and relay 29 to battery. Upon energizing, relay 29 opens the normally closed bridge across the conductors 90 and 92, at armatures 53 and 54, and, at the working contacts of the said armature, places the upper and lower windings of line relay 27 in bridge of the said conductors, the bridge in either case including the upper and lower le'tt windings of the repeating coil T. Line relay 27 now energizes, over the previously traced bridge across conductors 90 and 92 .in the operators circuit 0, and closes a cirthat release relay is now locked up to conductor 91, at armature 88, in series with spring 76, of release key K and its resting contact. As a further result of the energization of line relay 27, it closes, at armature 18, the following circuit: from grouml by way of the upper winding of line relay 107 of repeat-er D, resting contact of armature 136 and said armature, resting contact of armature 138 and said arn'iature, resting contact of armature 112 and said armature, upper and lower left hand windings of re peating coil T, upper and lower conductors of trunk line X, upper and lower righthand windings of repeating eo-il T, armature andv its working contact, armature 48 and its working contact, and the lower winding of supervisory relay 22 to battery. Supervisory relay 22, of repeater I) and line relay 107 of repeater D now energize in series over the above traced circuit. Supervisory relay 22, upon energizing, opens a point in the circuit of reversing relay 28,at armature 34c, and closes a circuit for relay 21, at armature 35. Upon energizing, relay 21, which corresponds to relay 110 of repeater D, closes a locking circuit for itself at an mature 33, and prepares a circuit for reversng relay 28, at armature 31.

In the repeater D line relay 107, upon energizing, in series with supervisory relay of repeater D, closes the circuit of release relay 108, at armature 128. Upon energizing, release relay 108 prepares a circuit for slow acting relay 106, at armature 130, and places ground on release trunk coiulu'ctor 194, at armature 129. This groundpotential extends to the test contact 191 and its multiples in the banks of the automatic switches having access to the toll line X, thereby guarding the said line against intrusion in the usual manner. A branch 01 this circuit extends to the busy lamp L" which becomes lighted, thereby ii'iiorniing the toll operator of the busy condition ol the toll line. It will be noted that the polarizing windings oi the polarized relay 174 of the operators circuit 0 and polarized rclay 111 of the repeater l), are energized at this little, but as before ated neither of the said relays is operated by current flowing in the polarizing winding alone. As a further result of the ei'lcrgization of release rclay 108, it con'ipletes, at armature 131, the following bridge across the conductors and 101: from comluctor 101, by way of the working contact or armature 131 and said armature, armature and its resting contact, lower right winding of repeating coil T, armature 114: and its resting contact, lower winding of electropolarized relay 111, resistance 141', resting contact of armature 113 and said armature, upper right winding of repeating coil T, and the working contact of armature 1.27 and said armature,

to conductor. 100. In response to the closure of this bridge across the coi'uluctors 5100 and 101, the line and iclease relays of the inconting toll. first selector E, Fig. 3, are energized in the usual manner therebypreparing the switch for operation. Electropolarized relay 111, however, is not energized at this time because the current flowing in either of its windings opposes that flowing in the other.

It will be seen now that the busy lamps L and L on either end of the toll line X are lighted: the said toll line is made busy to the automatic switches having access to it; and the incoming toll selector E associated with the toll line X in exchange No. 2, is made ready for operation, as result of the throwing key K in the operators circuit O in exchange No. 1, to the call out position.

The calling operator may now manipulate her calling device S in accordance with the proper digits, whereupon --the selectors I? and F and the connector H are operated in the usual manner to extend the connection to the line of substation A In this case the connector H which is a combination toll and" regular connector has only the operating characteristics of a regular conruazlor, such as connector H, and accordingly ringing current is inter-nrittently sent out to ring the bridged bell at the called sub.-tation in the usual manner.

In regard to the operation of the repeaters D and D in repeating the inunilees to the a-utcnuatic switches in exrhange No. :3, it may be said that the action is exzictly the same in this call as in the one previously dcscribed, with the obvious exception that the rc watcrs occupy reversed positions owing to the fact that the call is coming in to ex chauge No. 2 from exchange No. 1, in this case. a

The calling operator, having finished calling the number, may restore the key if to normal pos tion and wait tor the subscriber at ruhs tation A? to answer. When the key K is rcslorwl to normal position. the original energizing circuit of [release relay 80 is broken at spring 75, but the said relay is maintained energized over its prm'iously mentioned locking circuit. Springs 73 and 7 1, in returning to normal position, shift the bridge across: conductors 90 and 92 so as to include only the working contact of spring 87 and said spring, normally clozed contacts controlled by spring 7%,. left hand winding of electropolarized relay 79, iinped ance 60, normally closed contacts controlled by spring 73, and armature 80 and its working contact. lllectropolarized relay 70 open ates at this time, because its two windi assist each other and closes. at armature the circuit of supervisory lamp L where upon the said lamp becomes lighted.

low.

ing current and connect up the back bridge relay in the said connector- When this is done the back bridge relay in the connector H energizes and reverses the current flow in the line conductors extending to the connector H and consequently in the conductors 100 and 1-01 extending back to the repeater .D.- Electropolarized relay 111, the lower winding of which is included in a bridge across these conductors in the repeater D, now energizes because its two windings, which heretofore have opposed each other, are now energized in the same direction. Upon energizing, relay 111 closes a locking circuit for line relay 107, at armature 139, and shifts. the switch control circuit, at

' armature 138, from ground, by way of the upper winding of line relay 107, to battery, by way of the upper wind ng of supervisory relay 109. Since both, ends of the control circuit arenow connected to the same pole of battery, supervisory relay 109 of repeater D is not energized at this time and supervisory relay 22 0t repeater D deenergizes. Upon deenergizing, supervisory relay 22 closes the circuit of reversing relay 28', at armature 34. Upon energizing, reversing relay 28 reverses the conductors 90 and 92 as regards their connection with the windings of line relay 27, at armatures and 51. In response to this reversal, electrop'olarized relay 79 retracts its armature 85, thereby extinguishing the lamp L to give theoperator answering supervision. The operator, upon noting that the lamp L has become extinguished, knows that the called subscriber has answered and sheaccordingly throwsthe key K. to the listening position thereby operating springs 71 and 72 which connect her head set in bridge of the heavy talking conductors. She now converses with the subscriber at substation A and tells him to wait on the line while she calls the sul criber that desires to converse with him.

In order to call the subscriber at substation A the calling operator throws her key K to the calling position thereby operating the springs 6870 inclusive. Spring 70, upon being operated, closes a circuit for re lease relay 7,7 in series with spring 89 of release key K, and its resting contact. Release relay 77, upon energizing, prepares a locking-circuit for itself, at armature 83, and, at armatures 81 and 82, completes the following bridge across line conductors 93 and 95: from line conductor 95, by way of spring 67 and itsresting contact, working contact of armature 82 and'said'armature, working contact of spring 69 and said spring, impulse springs of the call ng device S, the secondary winding of the operators induction coil,

together with the associated resistance, spring 68 and, its working contact, armature 81 and its working contact, and the resting contact or spring 66 and said spring, to conductor 93. In response to the closure of this bridge, the line and release relays 0t selector E, Fig. 3, energize; prepare the switch for operation, and place ground on release trunk conductor 94: in the usual manner. The placing of a ground release trunk conductor 94 by the release relay of the said selector E establishes a locking circuit tor release relay 77, in series with the working contact of armature 83 and said armature, and the release key K, independent of spring of key K. v

The calling operator may now manipulate her calling device in accordance with the digits of the desired number whereupon the selectors E and F and the connector H are operated to give access to the line of sub station A. The connector H now sends ringing current out intermittently to ring the bridged bell at the called substation.

Having finished dialling the numb-er, the operator restores the key K to normal position. thereby removing her head set and associated calling device from the bridge across conductors 93 and 95 and inserting the impedance 61 and the right hand winding of electropolarized relay 78 therein. The current is now flowing through the two windings of relay 78 in the same direction and accordingly the armature G4. is operated and the supervisory lamp L becomes lighted.

When the subscriber at substation A re sponds to the ringing of his hell by IQDJOVQ ing his receiver, the connector H reverses the direction of current How in the established connection, and consequently in conductors 93 and .95 and the bridge across the said conductors in the operators circuit O. Electropolarized relay 78 now retracts its armature, thereby extinguishing the lamp L so as to give the operator answering supervision. The two subscribers may now converse with each other as desired After the conversation is finished the two subscribers replace their receivers. When the receiver is replaced at substation A the consequent reversal of current flow causes the electropolarized relay 78 in the operators circuit O.to reoperate its armature 84 and light the lamp L, whereupon the operator releases the connection by momentarily operating the release key K.

lVh-en the receiver is replaced at substation A the consequent reversal of current flow causes the electropolarized relay 111 to retract its armatures, thereby opening the locking circuit of line relay 108, at armature 139, and closing at armature 138, the initial circuit of the line relay 107, in series with the supervisory relay 22 of repeater 1). Line relay 107 is now maintained energized over this circuit and superwisory relay 22 energizex As a result the energization of super sory relay 22, the circuit of reversing relay 28 opened at armature 34;. Relay 28, upon deenci 'gizingr, reverses the direction of current flow in the conductors 90 and 9:2 to normal, whereupon electropolarized relay 7?) attracts its armature, thereby lighting the super sory lamp L.

In order to release, the connection, the operator momentzniily operates the release key K whereupon the release relay deener- ,q izes; opens its locking circuit at armature 88: and, at armatiu'es 86, and 87, opens the bridoge across conductors 90 and 92, with the result that the line relay 27 deenergizes; opens the. control circuit. at armature 48; and at armature 49- opens the circuit of release relay 26. Upon deenergizing, release relay 26 removes ground from conductor 91, and busy lamp L accordingly becomes extinguished and all the relays of repeater D. that have not already done so assume normal position. a result of the opening of the control circuit by line relay 27, line relay 107 of repeater D deenergizes opens the circuit of release relay 108, at armature 128; and, at ari'naturc 127, opens the bridge, across conduct/ore and 101. The switches E" F and H now restore themselves to normal position in the usual manner. Release relay 108 upon deenergizinpg, removes ground "from release trunk conductor 19 11, at armatare 121, whereupon, the busy lamp L becomes exting hed and all the relays of re peater D that have not already done, so assume normal position. The entire conneotion is now released and all the apparatus used is restored to normal position.

If we assume that the fillll Fitl llJGl at substation A in the connection inst described had d ired to. obtain connection with. some subscriber in exchange No. E}, (Fig. 3) the operations performed by the calling operator would, (litter only in that she calls two extra digits which are the ones which give. access to e:-;changie No. 3. Assuming that the. operator in. exchange No. l extending a connection to a. subscriber in exchange No. 3 by way ot? the trunk line X, and that she has. already thrown her call out key, with the result that the repeaters D, and D and the selector E are made ready "tor operation, she operates her. calling device in accordance with the digit t). whereupon the selector lil raises its wipers to the tenth level and retates them in search of an idle trunk line. lVe shall assume that the trunk line extending to the toll switching: selector F is the first one found idle and consequently the one selected. That being the. case, when the operator operates her calling device for the second digit in the desired number, which in this case is the digit 1, the selector F raises its shaft and wipers until the latter stand opposite the first level of bank contacts and automatically rotates them in search of an idle trunk line. Assuming now. that the trunl: line extending to the, repeater D? is the first one found idle and consequently the 191, andv 1.92, associated \vith repeater D, andv the. repeater D will. operate the. same as the repeater If) (lid when the operator in exchange 0. 2 threw. the. key K to the call. out position. Consequently, the repeater places ground on its associated release, trunk conductor, thereby lighting. the, busy lamp in. the operators c rcuit and at the samev time places battery onv the trunk line Z through its supervisory relay so, as to operate the line relay of the repeater D The line relay of the repeater D? now energizes and closes a circuit for the release relay which, upon energizing, lights the busy lamp associated, with. the operators circuit so as'to inform the operator in, exchange No 3; of busy condition ot the trunk line The repeater D also. closes a bridge across the line conductors of the trunk line extending to the incoming toll selector E at this time, and consequently the. said selector is made. ready tlfor operation in the usual manner. The calling operator now manipulates her calling device in accordance with the remaining digits of the. desired number here: upon the selectors E and F and the connector H are operated to give. access to the called line in the usual manner.

Vhen the called subscriber answers, the resulting reversal, of current flow causes the electropolarized relay in repeater D5 to function, with the result that the supervisory relay connected in the control circuit in the repeater D is caused to deenergize. result.- ing in a reversal of the direction of the current flowing in the trunk line leading to the repeater D? and consequently in the conductors 100 and 10 1 of the repeater D. It easily seen. that from this point the operation continues in exactly the same manner as i did when the called subscriber was in ex; change No. 2.

ll will be noticed that no n'ovisions hare been made for signalling back and forth between the toll; operators in the diflerent exchan ges by ringing. This resulhliowever, is accomplished in the present toll trunking system in a different manner. U pon referring' to 3. three dotted rectangles 10,11, and 12, will be seen. Each of these rectanQ gles is supposed to represent certain equip ment at the operators posit-ion that is used in answering a call extended to her by a toll operator in some other exchange. It shown only diagrammatically in Fig. 3 but in fact is similar to. thev equipment referred int) to bythe reference character J in Fig. 3 of the drawings accompanying the patent to \V-illis, hereinbefore referred to, To illustrate just how this is done we shall assume that the tolloperator in exchange No.1 wishes to obtain some information from the toll operator in exchangeNo. 2. To'do this the calling operator dials thennmber O0 whereupon theselectors and F are operated to give access to a trunk line extending to the operators position and terminating in the dotted rectangle 11; lVhen this is done the associated lamp is lighted. The operator, upon seeing the lighted lamp, throws her key, thereby extinguishing the lamp and connecting her head set with the trunk line. Similarly the operator in exchange No. 1 may extend a connection to the operator in exchange Nos 8, by dialling the numberOlO whereupon the selectors E F and E, are operated to give access to a trunk line extending to the operators equipment, designated by,,the reference character 12 in exchange No. 3. Obviously the operator in exchange No. 2 may extend a connection to an operator in either exchange No. 1 or exchange No. 3 by dialling the digit 0. It is also equally evident that the operator in exchange No. 3 may extend a connection to the operator in exchange No. 2 bydialling the No. 0001' that she may extend a connectionto the operator in exchange No. 1 by dialling the number 010.

A brief description, of the method used by a night operator in exchange No. 2 in handling calls, will now be given. Assuming that the traffic over the toll lines terminating in exchange No. 2 is not more than can be handled by two toll operators, only two positions, obviously, will be required in said exchange and one operator can easily take care of the small amount of'tralfic whichis usual at night, by presiding over the two positions. In the case, howeven'that there are great number of positions in exchange No. 2 an operator cannot reach all the toll lines from any one position. In this event it becomes necessary to provide means whereby she may extend a connection to any toll line from a given point. In keeping with the spirit of the invention, a number of link circuits not shown) have been provided. Each link is substantially the same as the operat'oris circuit O with the exception that one end connected directly with a toll switching selector such as toll switching selector F instead of being connected with a repeater such as the repeater D.

lVhen an operator who is provided with these before mentioned link circuits wishes to extend a connection over any toll line which is terminated in the banks of the before mentioned toll switching selector, she dials the p'rppcr'digit, thereby causing the switching the toll service trunking system in the usual manner.

Referring now to relay 21 of repeater D, and relay 110 of repeater D, the function of either of these relays in connection with an outgoing call will be explained more in detail. It often happens that when toll lines, such as the toll line X, connect two small exchanges, the toll operator is dispensed with and the subscribers themselves are given ac cess to the toll lines and are allowed to dial their own connections from one exchange to the other, and in order to make the proper charges, each line may be equipped with a meter that operates in response to a reversal of current which takes place when the called subscriber answers. If the repeaters, such as the repeaters D and D, were used in such a system without being equipped with relays, such as the relays 21 and 110, and if the as sociated trunk line, such as the trunk line X, were'open when a subscriber makes a call the supervisory relay on the calling end of the trunk line would not be energized and the reversing relay, such as the reversing relay 28 of repeater D or reversing relay 103 of repeater D, would operate immediately and cause the current flow in the calling line to be reversed in the same manner as when a call is answered. This would obviously operate the calling subscribers meter, thereby charging him for a connection which he did not obtain. Taking the repeater D for example, when'the saic repeater is equipped with a relay such as the relay 110, it is impossible for an open interexchange trunk line to cause a reversal of current in the calling line owing to the fact that the circuit of the reversing relay 103 is held open at armature 135 until relay 110 energizes, which it cannot do if the trunk line X is open. H

Having fully described and ascertained the features of the invention, what is con sidered to be new and desired to have protected by Letters Patent will be pointed out in the appended claims.

Vhat I claim is:

1. In an automatic telephone exchange system, a toll line incoming from another exchange, a local trunk line normally disconnected from said toll line, operator controlled switching means for connecting said local trunk with local subscribers lines, and an operators link circuit for connecting said toll line and local trunk to establish toll connections, said link circuit being indiassociated With and individual to both the said toll line and the said local trunk for connecting the two together, operators equipment associated with said link circuit for use in. establishing toll connections, and. a toll repeater connected in multiple with said link circuit, whereby said switches may be controlled over said toll. line independent of said link circuit.

3. In an automatic telephone exchange system, a group of toll lines incoming from another exchange, a toll switchboard whereat saicltoll lines terminate, an equivalent group of local trunk terminating at said switchboard, a plurality of operators link circuits connecting said toll lines and local trunks, whereby each local trunk made individual to, a particular toll line, a plurality of re peaters connected to said toll line in multiple with said link circuits, separate sets of talking conductors extending through said link circuits and repeaters, automatic switches for extending said local trunks to local subscribers lines to establish toll connections, and circuits whereby said switches may be controlled either from said link circuits or fromsaid repeaters.

a. In an, automatic telephone exchange system, a group of toll lines incoming from another exchange, a toll switchboard whereat said toll lines terminate, an equivalent group of local trunks terminating at said switchboard, a, plurality of operators link circuits connecting said toll lines andlocal trunks, whereby-each local trunk is made individual to a particular toll line, automatic switches for extending said local trunks to local: subscribers lines to establish toll conncctions, operators equipment associated with said link circuits for controlling said switches, and other means for controlling said switches to establish connections independent of said link circuits.

5. In an automatic telephone exchange system, a group of toll lines incoming from, another exchange, a toll switchboard whereat said toll lines terminate, an equivalent group oflocaltrunks terminating at said switchboard, a plurality of operators Linkcircu its connecting said toll lines and local trunks, whereby each local trunk is made individual to particular. toll. line, automatic switches for extending said local trunks to locahsub scribers, lines to establish toll, connections, and operators talking, ringing, switch controlling, and supervisory equipment asso-, ciated with said link circuits.

incense 6. In an automatic telephone. exchange system, a toll line incoming from another exchange and extending through an auto.- matic impulse repeater to an automatic switch, an operators link circuit bridged around said repeater, and means for connecting the said toll line with said switch for talking purposes either by way of said repeat-er or by way of said link circuit.

7. In an automatic telephone exchange system, a toll line incoming from a-notl'ier exchange, two automatic switches permanently associated ith said toll line and individual thereto, an automatic impulse repeater and an operators link circuit, both of which are permanently associated with and individual to said toll line, means 101: connecting said toll line with one of said switches by way of. said repeater and means for connecting the said toll line with the other switch by way ofsaid link circuit.

8. In a telephone system, a trunk line connecting two exchanges, meansppel'ated when the trunk line is taken for use at the first exchange for establishing a ground return control circuit over said trunk line, automatic switch-cs at the. second exchange controlled over said control circuit to establish connection with a called subscribers line, a reversing relay in the first exchange, means actuated when the called. subscriber answers for stopping the flow of current in said control circuit to control said relay, and a second relay and circuit connections therefor effective to prevent said reversing relay from being affected in case saidtrunk line is open when the same is taken for use.

9. In a telephone system, a trunk line, an automatic impulse repeater included in said trunk line, two branches connected to said trunk line on opposite sides of said repeater, and an operators link circuit individual to said trunk line for connecting said branches.

10. In a telephone system, a trunk line comprising two normally disconnected sections, an automatic repeater at the junction of said sections for repeating impulses from one section to another, a branch connected to each section, and an operators link circuit individual to said -trunk line. for connecting said branches.

11. In a telephone system, an automatic impulse repeater, a trunk line comprising two talking conductors extending through said repeater, two talking branches connected to said. talking conductors, on oppo-- site sides of said repeater. and an operators link circuit comprising talkin, conductor: for connecting said branches, said link circuit being individual to said branches.

12. In a telephone exchange system, an automatic switch, a trunk line incoming to the exchange. two parallel talking circuits permanently connected to said switch at one end and to said trunk line at the other end,

ing them together to establish talking con nections, and means for setting up other talkingconnections over said trunk line in either direction, said talking connections excluding said link circuit.

14. In a telephone system, a calling oflice and acalled oflice. a trunk line connecting said oflices, an electro-responsive device in the calling ofiice, a relay in the calling o-fiice,

means inthe calllng office for closingan energizing circuit for said relay lncluding a i conductor of said trunk line, a second relay energized responsive to the operation of the first relay, means in the called ofiice for deenergizing said first relay, and a circuit for said device closed responsive ,to the first rclay being deenergized when the second relay is energized. I

15. In a telephone system, a control circuit extending to a distant point, a primary supervisory relay included in said control circuit. means for energizing said primary supervisory relay by closing said control circuit at the near end thereof, a circuit-preparing relay operated responsive to the energization of said primary superyisory relay, m-eansat the distant end of said control circuit "for opening the same to deenergize said primary supervisory relay, a secondary supervisory relay, and acircuit for said secondary supervisory relay including contacts closed by said primary supervisory relay when it is deenergized and contacts closed by said circuit-preparing relay when it is energized. r

16. In a telephone system, a control circuit extending to a distant point, a primary supervisory relay included in said. control circuit; means for energizing said primary supervisory relay by closing said control circuit at the nearend thereof, a circuit-preparing relay operated responsive to the energization of said primary supervisory relay,.means at the distant end of said control i circuit for opening the; same to deenergize said prin'iary SlIPGIVISOIyJGltIY, a second- ;ary supervisory relay. a circuit; for said secondary supervisory relay including contacts closed by said primary supervisory relay when it is deenergized and contacts closed by. said circuit-preparing relay when it is energized, means for producing a series of interruptions in said control circuit after the closure thereof and prior to said opening at the distant end, and means for preventing the operation of said secondary supervisory relayfresponsive to such interruptions.

17. In a telephone system, a first exchange and a second exchange, a trunk line connecting said exchanges, a control circuit in cliiding a conductor 0t said trunk line, a1-

ternate branches for said control conductor at the second exchange maintained at difi 'erent potentials, two relays connected in said branches, respectively, means at the first exchange for placing a potential on said contrel conductor to bring about the operation of the relay in the connected branch at the second exchange, means responsive to the 0perati'on 'ot' the last named relay for opening a point in the disconnected branch, for

shifting the control conductor to the alternate branch, and for subsequently closing the open point in the last named branch.

.18. Ina telephone system, a control conductor having alternate branches, a. relay associated with each branch, said control conductor being connected to the first branch, means controlled over said control conductor from the distant end for operating the relay associated with the first branch, meansresponsive to the operation of said relay for disabling the relayin the second branch from operating. tor shifting the said conductor from the iirstbranch to the second branch, and for subsequently enabling the relay in the second branch to operate again.

19. In a telephone system, a trunk line, two branches for said trunk line, means controlled over said trunk line and one of its branches forsettiiig up a talking connection extending to a called line and including said trunk line and said one branch, and controlled in another case over the other'branch independent of said trunk line and said one branch for setting up a talking connection. extending to the same called line and including said trunk line and said other branch.

20. In a telephone system, a trunk line having two branches at one end, means for connecting a calling line to said trunk line at the distant end, means including an auto matic switch for extending a connection from said line to a called line by way oi one cl said branches, and means ichiding said automatic switch i or extending; a connection from said line to the same called line by way of the other oi? said branches.

21. In a telephone system, a line, two branches for said line, means including an aiitoi'i'iai'iic switch having a wiper individual to said trunk line and common to said branches for setting up a connection from said'liiie to the same 'alled line over either of said branches.

22. In a: telephone system, a trunk line divide-d int-o two sections, parallel tallrii'in' branches connecting such sections, and in dividual to one section, and means controlled over either branch for setting; up a talkin; connection including in serial relation both sections of said trunk line and the over the branch through which the connection is set up. I

24. In a telephone system, a trunk line connect-nugtwo exchange, a manual SWltCllbOttlCl in the second exchange, a branch of said trunk line in the second exchange extending to an autonatic switch individual to said trunk line, and a qecond branch individual to said trunk line and extending to said switch via said. mamial switchboard.

25. In a telephone systen'i, a tail to tail connection between two automatic switches including an nmcratots link circuit, two locking seizingrelays in said link associated with said switches. respectively, and two non-locking keys tor unlocking said relays respecti vely.

26. In a telephone system, an operators link circuit, automatic twitching-mechanism tor extendi u; a connection therefrom to a called line, a switch control circuit including a comjhlctor of said link circuit, a sell locking relay controlling a normally open point in said link circuit, a Ctllllt'lfjf device ommon to said link and other similar links, a key individual to said link tor connecting said falling novice insaid control circuit. and for nrergizing said self locking; relay, and a nonloc :ing key to; subsequently unlocking said relay.

2?. In a telephone system, a trunk line diuded into two sections, parz-illel talking launches connectin: such sections and indiv'dual to one sectioi'i, and automatic switching; mechauis'an controlled over either talking); ljni'anch .ior setting up a telephone con ncction including! both trunk line sections.

In a. combined automatic and manual teleyhonc "vsten'l, a trunk line divided into two parallel intermediate sectwo sectio. tions connecting the first mentioned sections and individual to said trunk title, and switch (out said intermediate .rol minus in each ot sections.

In a combined automatic and manual telephone systeu'i, a trunk line divided into two sections. two parallel intermediate scctions connecting the first mentioned sections, and supem l ry m ans in each of said internu-zdiate sections.

30. In a combined automatic .nd manual telephoi'ie system, a trunk line divided into two sections, two pa 'allel intermediate sections connecting the/first mentioned sections and individual to' said trunk line, one of said sections, an operators ing said calling device to one of Said sections.

32. In a combined automatic and manual telephone system, a trunk hne divided into two sections two )arz llel intermediate sections connecting the tirst mentioi'iedsections and individual to said trunk line, one of intermediate sections being divided into two calling device, and said *alling device said divided intermeans for connecting with either section of mediate section.

353. In a combined automatic and inanual telephone "tent, a trunk line d. into two set'ti us, two parallel intermediate sections connecting the first i'nentioned scctions and imflividual to said trunk line, an opcratm' s calling; device. means for com'iectinc: said calling device to one oil said sections, and means in the other intermediate section. tor repeating to said trunk line impulses prodiuretl by said czlling device.

34-. In a telephone system, a trunk line incoming; to a telt-iphone exchange, two b'anches vtor said trn it; line in said exchange, an automatic 'llllPUlSO repeater in one branch arranged to repeat impulses re ceived over said trunk line, and an opt 'ators link circuit in the other brancl'l' individual to said trunk line.

35. In a telei ihone em, a trunk lire incoming to a telephone exchange, two b1."c nches connected to said trunk line, automatic switching meehs-mism in said exchange operable over one branch, and an operatons link circuit. in the other branch. individual to said trunkliuc.

36. In a telephone system, a trunk line incoming to a l't ltl llll'illt. exchange, two branches con nectml to said trunk line, uto" n'iatic switching mechanism in said cxchai' re operable over one branch, an operatofls link circuit in the other b anch individmd to said trunk line, and switchcontrolling means associated with said link circuit.

37. In a. telephone system, a trunk line incoming; to a telephone exchange, vo branches extending from said trunk line, a. toll service trunking sy tem in said enchange, a separate trunking system in said exchange, one branch of said trunk line being); o

38. In a telephone system, a trunk iine incoming to a telephone exchange, two branches extending from said. trunk lines, a toll service trunking system in said ex change, a separate trunking system in said exchange, one branch of said trunk line being extended to a first order switch in said toll service trunking system, the other branch of said trunk being extended to a first order switch in the other trunking system, and an operators link circuit inserted in and individual to the branch extending to the first order toll service switch.

In Witness whereof, I hereunto subscribe my name this 30th day of June, A. D. 1921.

JOHN WICKS. 

